MKS INSTRUMENTS, INC.

2 Tech Drive, Suite 201

Andover, Massachusetts 01810

April 5, 2023

Dear Shareholder:

You are cordially invited to attend the 2023 Annual Meeting of Shareholders of MKS Instruments, Inc. to be held on Tuesday, May 16, 2023 at 10:00 a.m., Eastern Time, at our headquarters at 2 Tech Drive, Suite 201, Andover, Massachusetts 01810.

The attached notice of Annual Meeting and proxy statement describe the business to be transacted at the Annual Meeting and provide additional information about us that you should know when voting your shares. The principal business at the Annual Meeting will be (i) the election of two Class III Directors, each for a three-year term, (ii) the approval, on an advisory basis, of executive compensation, (iii) an advisory vote regarding the frequency of advisory votes on executive compensation, and (iv) the ratification of the selection of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the year ending December 31, 2023.

Whether or not you plan to attend the Annual Meeting, please carefully review the attached proxy materials and take the time to cast your vote.

On behalf of MKS, I would like to express our appreciation for your continued interest in our Company.

MKS INSTRUMENTS, INC.

2 Tech Drive, Suite 201

Andover, Massachusetts 01810

NOTICE OF 2023 ANNUAL MEETING OF SHAREHOLDERS

TO BE HELD ON TUESDAY, MAY 16, 2023 at 10:00 A.M. EASTERN TIME

To our Shareholders:

The 2023 Annual Meeting of Shareholders of MKS INSTRUMENTS, INC., a Massachusetts corporation, will be held on Tuesday, May 16, 2023 at 10:00 a.m., Eastern Time, at our headquarters at 2 Tech Drive, Suite 201, Andover, Massachusetts 01810, for the following purposes:

The shareholders will also act on any other business as may properly come before the meeting.

We provide access to our proxy materials over the Internet under the U.S. Securities and Exchange Commission’s “notice and access” rules. As a result, we mail to our shareholders a Notice of Internet Availability of Proxy Materials, which we refer to as the Notice. We are mailing the Notice on or about April 5, 2023, and it contains instructions on how to access the proxy statement and our Annual Report for the fiscal year ended December 31, 2022, which we refer to as the 2022 Annual Report, over the Internet. The Notice also contains instructions on how our shareholders can receive a paper copy of our proxy materials, including this proxy statement, our 2022 Annual Report, and a form of proxy card or voting instruction card. All shareholders who do not receive the Notice, including shareholders who have previously requested to receive paper copies of proxy materials, will receive a paper copy of the proxy materials by mail unless they have previously requested delivery of proxy materials electronically.

The Board of Directors has fixed the close of business on March 8, 2023 as the record date for the determination of shareholders entitled to notice of, and to vote at, the Annual Meeting and any adjournment or postponement thereof. Your vote is important no matter how many shares you own. Whether or not you expect to attend the meeting, we urge you to vote your shares.

If you are a shareholder of record, you may vote by using the Internet or calling the toll-free telephone number as described in the instructions included in your Notice, or, if you received a paper copy of the proxy materials, by completing, signing, dating, and returning your proxy card or voting instruction card. If you are a beneficial shareholder (meaning the shares you own are held in “street name” by a bank, broker, or other nominee), you may vote by following the instructions your broker, bank, or other nominee provides to you. Your prompt response is necessary to ensure that your shares are represented at the meeting. You can change your vote and revoke your proxy any time before the polls close at the meeting by following the procedures described in the accompanying proxy statement.

Andover, Massachusetts

April 5, 2023

TABLE OF CONTENTS

i

ii

MKS INSTRUMENTS, INC.

2 Tech Drive, Suite 201

Andover, Massachusetts 01810

PROXY STATEMENT

This proxy statement is furnished in connection with the solicitation of proxies by the Board of Directors of MKS Instruments, Inc., a Massachusetts corporation, for use at the 2023 Annual Meeting of Shareholders to be held on Tuesday, May 16, 2023 at 10:00 a.m., Eastern Time, at our headquarters at 2 Tech Drive, Suite 201, Andover, Massachusetts 01810, and at any adjournment or postponement thereof, which we refer to as the 2023 Annual Meeting. References in this proxy statement to “we,” “us,” the “Company,” or “MKS” refer to MKS Instruments, Inc. and its consolidated subsidiaries.

All proxies will be voted in accordance with the applicable shareholder’s instructions. If no choice is specified in the proxy, the shares will be voted in favor of the matters set forth in the accompanying Notice of 2023 Annual Meeting of Shareholders. Any proxy may be revoked by a shareholder at any time before its exercise by delivery of written revocation to the Secretary of MKS or by voting during the 2023 Annual Meeting. Attendance at the 2023 Annual Meeting will not in itself be deemed to revoke a proxy.

We provide access to our proxy materials over the Internet under the “notice and access” rules of the U.S. Securities and Exchange Commission, which we refer to as the SEC. As a result, we mail to our shareholders a Notice of Internet Availability of Proxy Materials, which we refer to as the Notice. We are mailing the Notice on or about April 5, 2023. The Notice contains instructions on how to access the proxy statement and our Annual Report for the fiscal year ended December 31, 2022, which we refer to as the 2022 Annual Report, over the Internet. The Notice also contains instructions on how our shareholders can receive a paper copy of our proxy materials, including this proxy statement, our 2022 Annual Report, and a form of proxy card or voting instruction card. All shareholders who do not receive the Notice, including shareholders who have previously requested to receive paper copies of proxy materials, will receive a paper copy of the proxy materials by mail unless they have previously requested delivery of proxy materials electronically.

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL MEETING OF SHAREHOLDERS TO BE HELD ON MAY 16, 2023

This proxy statement and the 2022 Annual Report are available for viewing, printing, and downloading at investor.mks.com/annual-meeting-materials.

A COPY OF OUR ANNUAL REPORT ON FORM 10-K FOR THE YEAR ENDED DECEMBER 31, 2022 AS FILED WITH THE SEC, EXCLUDING EXHIBITS, WILL BE FURNISHED WITHOUT CHARGE TO ANY SHAREHOLDER UPON WRITTEN REQUEST TO: INVESTOR RELATIONS DEPARTMENT, MKS INSTRUMENTS, INC., 2 TECH DRIVE, SUITE 201, ANDOVER, MA 01810. EXHIBITS WILL BE PROVIDED UPON WRITTEN REQUEST AND PAYMENT OF AN APPROPRIATE PROCESSING FEE.

VOTING OF SECURITIES AND VOTES REQUIRED

At the close of business on March 8, 2023, the record date for the determination of shareholders entitled to notice of, and to vote at, the 2023 Annual Meeting, there were issued and outstanding and entitled to vote 66,669,254 shares of our common stock, no par value per share, which we refer to as our Common Stock. Each outstanding share entitles the record holder to one vote on each matter submitted at the 2023 Annual Meeting.

In order to transact business at the 2023 Annual Meeting, we must have a quorum. Under our Amended and Restated By-Laws, or our By-Laws, the holders of a majority of the shares of Common Stock issued and outstanding and entitled to vote at the 2023 Annual Meeting shall constitute a quorum for the transaction of business at the 2023 Annual Meeting. Shares of Common Stock held by shareholders present at the 2023 Annual Meeting or represented by proxy (including “broker non-votes” and shares that abstain or do not vote with respect to a particular proposal to be voted upon) will be counted for purposes of determining whether a quorum exists at the 2023 Annual Meeting. If a quorum is not present, the meeting will be adjourned until a quorum is obtained.

For the election of directors (Proposal One), you may vote “For” or “Withhold” for each director nominee. The affirmative vote of the holders of a plurality of the votes cast on the matter is required for the election of directors; provided, however, any director nominee who receives a greater number of withhold votes than affirmative votes, which we refer to as a Majority Withheld Vote, in an uncontested election must offer to tender to the Board of Directors his or her resignation promptly following the certification of election results. The Board of Directors must accept or reject a resignation within 90 days following the certification of election results and publicly disclose its decision. Accordingly, the nominees who receive the highest number of votes of the shares present, in person or by proxy, and entitled to vote shall be elected to the available Class III Director positions, and in the event any nominee receives a Majority Withheld Vote, the resignation policy will apply as summarized here and as set forth in Section B.4 of our Corporate Governance Guidelines, which are posted on our website at www.mks.com/corporate-governance under Corporate Governance Documents.

For the advisory vote on executive compensation (Proposal Two) and the ratification of PricewaterhouseCoopers LLP (Proposal Four), you may vote “For,” “Against” or “Abstain.” For the advisory vote regarding the frequency of advisory votes on executive compensation (Proposal Three), you may vote for “1 Year,” “2 Years,” “3 Years,” or “Abstain.” Proposal Two, Proposal Three, and Proposal Four require the affirmative vote of the holders of a majority of the votes cast on the matter. However, regarding Proposal Three, if none of the three frequencies (every one, two, or three years) receives a majority of the votes cast on this proposal, we will consider the frequency receiving the greatest number of votes to be the frequency recommended by shareholders. Proposal Two and Proposal Three are non-binding proposals.

Shares held by shareholders who abstain from voting as to a particular matter, and “broker non-votes,” which are shares held in “street name” by banks, brokers, or other nominees who indicate on their proxies that they do not have discretionary authority to vote such shares as to a particular matter, including the election of directors, the advisory vote on executive compensation, and the advisory vote regarding the frequency of advisory votes on executive compensation, will not be counted as votes in favor of, or as votes cast for, a matter. Accordingly, we expect abstentions and broker non-votes will have no effect on the voting on a matter that requires the affirmative vote of a majority of the votes cast on the matter. If the shares you own are held in street name by a bank, broker, or other nominee, then your bank, broker, or other nominee, as the record holder of your shares, is required to vote your shares according to your instructions. In order to vote your shares, you will need to follow the instructions your bank, broker, or other nominee provides to you.

For additional details about voting and attending the 2023 Annual Meeting, please see “Voting and Meeting Information” below.

VOTING AND MEETING INFORMATION

The following sections provide additional details about voting and attending the 2023 Annual Meeting.

Voting Your Shares

If you are a shareholder of record, you may vote your shares in any of the following ways:

		Internet
		You may vote your shares in advance of the 2023 Annual Meeting via the Internet by accessing our online portal at www.proxyvote.com. Proxies submitted via the Internet must be received by 11:59 p.m. Eastern Time on May 15, 2023.
		Telephone
		You may vote your shares in advance of the 2023 Annual Meeting telephonically by calling 1-800-690-6903 and following the instructions on your proxy card. Proxies submitted by telephone must be received by 11:59 p.m. Eastern Time on May 15, 2023.
		Mail
		If you received a paper copy of the proxy materials, you may vote your shares in advance of the 2023 Annual Meeting by completing, signing, dating, and returning your proxy card or voting instruction card. Proxies submitted via mail must be received by May 15, 2023.
		In-Person at the 2023 Annual Meeting
		You may vote your shares during the 2023 Annual Meeting by (i) if you received a paper copy of the proxy materials, completing your proxy card or voting instruction card or (ii) if you did not receive a paper copy of the proxy materials, completing a ballot to be provided by the Company at the meeting. If you have previously submitted your proxy and you vote your shares in accordance with these instructions during the 2023 Annual Meeting, your previously submitted proxy will be revoked.

If you are a beneficial shareholder (meaning the shares you own are held in “street name” by a bank, broker, or other nominee), your bank, broker, or other nominee will provide a vote instruction form to you with this proxy statement, which you may use to direct how your shares will be voted. You must instruct your bank, broker, or other nominee how to vote with respect to the election of directors, the executive compensation advisory vote, and the advisory vote regarding the frequency of advisory votes on executive compensation; your bank, broker, or other nominee cannot exercise its discretion to vote on these matters on your behalf. Many banks and brokers offer the option of voting over the Internet or by telephone, instructions for which would be provided by your bank or broker on your vote instruction form. You may only vote your shares in-person at the 2023 Annual Meeting if you obtain a proxy issued in your name from your bank, broker, or other nominee. For instructions on how to revoke or change your vote, you should contact your bank, broker, or other nominee.

Attending the 2023 Annual Meeting

Admission of shareholders of record and beneficial shareholders to the 2023 Annual Meeting will begin at 9:45 a.m. Eastern Time. Shareholders of record who wish to attend the meeting should be prepared to present photo identification and beneficial shareholders who wish to attend the meeting should be prepared to present photo identification and a letter from their bank, broker, or nominee confirming beneficial ownership of shares of our Common Stock.

Proxy Materials

You can view and download our proxy materials and 2022 Annual Report at our online portal, available to shareholders at www.proxyvote.com.

Shareholder List

During the 2023 Annual Meeting, a complete list of our shareholders of record will be available for viewing by shareholders for any purpose germane to the 2023 Annual Meeting. Shareholders submitting any such request will be asked to include the 16-digit control number found on their proxy card, voting instruction card, or Notice.

Whether or not you plan to attend the 2023 Annual Meeting, we urge you to vote your shares over the Internet or by telephone, or complete, sign, date, and return the proxy card in the accompanying postage-prepaid envelope if you received a printed proxy card. A prompt response will greatly facilitate arrangements for the 2023 Annual Meeting and your cooperation will be appreciated. Shareholders who attend the 2023 Annual Meeting may vote their shares at the 2023 Annual Meeting even if they have previously sent in their proxies.

PROPOSAL ONE – ELECTION OF DIRECTORS

Our By-Laws provide for a Board of Directors that is divided into three classes. The term of the Class III Directors expires at the 2023 Annual Meeting, the term of the Class I Directors expires at the 2024 Annual Meeting of Shareholders, and the term of the Class II Directors expires at the 2025 Annual Meeting of Shareholders. Our Board of Directors, upon the recommendation of our Nominating and Corporate Governance Committee, has nominated Peter J. Cannone III and Joseph B. Donahue to serve as Class III Directors for a term to expire at the 2026 Annual Meeting of Shareholders. Mr. Cannone and Mr. Donahue currently serve as directors. Each nominee has consented to being named herein and, if elected, to serve as a director until his successor is duly elected and qualified.

Geoffrey Wild, who currently serves as a Class III Director, is not standing for re-election to the Board of Directors. The Board of Directors previously approved a decrease in the size of the Board of Directors effective immediately prior to the 2023 Annual Meeting, which eliminates the vacancy that would have existed at the 2023 Annual Meeting. Proxies cannot be voted for a greater number of persons than the number of nominees named in this proxy statement.

Shares represented by all proxies received by the Board of Directors and not so marked as to withhold authority to vote for an individual director will be voted (unless one or more nominees are unable or unwilling to serve) for the election of the nominees named below. The Board of Directors expects that each of the nominees named below will be available for election, but if any of them is not a candidate at the time the election occurs, it is intended that such proxies will be voted for the election of a substitute nominee to be designated by the Board of Directors.

THE BOARD OF DIRECTORS BELIEVES THAT APPROVAL OF THE ELECTION OF PETER J. CANNONE III AND JOSEPH B. DONAHUE TO SERVE AS CLASS III DIRECTORS IS IN THE BEST INTERESTS OF MKS AND OUR SHAREHOLDERS AND THEREFORE RECOMMENDS A VOTE “FOR” BOTH NOMINEES.

DIRECTORS

Set forth below are the names and ages of each member of our Board of Directors (including those who are nominees for election as Class III Directors) and the positions and offices they hold with the Company. In addition, set forth below are biographies for each continuing director and director nominee, which include each individual’s principal occupation and business experience during at least the past five years, the names of other publicly held companies on which the individual currently serves, or in the past five years has served, as a director, the year each individual joined our Board of Directors, and information about each individual’s specific experience, qualifications, attributes, or skills that led the Board of Directors to conclude that he or she should serve as a director of MKS. Information with respect to the number of shares of Common Stock beneficially owned by each individual, directly or indirectly, as of March 8, 2023, appears in this proxy statement under the heading “Security Ownership of Certain Beneficial Owners and Management.”

Name

Age

Position

Audit Committee

Compensation Committee

Nominating and Corporate Governance Committee

Class to Which Director Currently Belongs

Rajeev Batra

55

Director

I

Peter J. Cannone III*

57

Director

III

Gerald G. Colella

66

Chair

I

Joseph B. Donahue*

64

Director

III

John T.C. Lee

60

Director, President and CEO

II

Jacqueline F. Moloney

69

Lead Director

II

Elizabeth A. Mora

62

Director

I

Michelle M. Warner

56

Director

II

Geoffrey Wild

66

Director

III

Chair

Member

Director Skills, Experience and Background

MKS enables technologies that transform our world, delivering foundational technology solutions to leading edge semiconductor manufacturing, electronics and packaging, and specialty industrial applications. As we discuss below under the heading “Corporate Governance – Director Candidates,” the Nominating and Corporate Governance Committee is responsible for evaluating the appropriate skills, experience, and background that MKS seeks in Board members in the context of our business and the existing composition of the Board of Directors. This evaluation includes numerous factors, such as integrity, business acumen, knowledge of our business and industries, effectiveness, experience, diligence, conflicts of interest, and the ability to act in the interests of all shareholders.

Listed below are the skills and experience that we consider important for our directors given our current business and organizational structure. The continuing directors’ and director nominees’ biographies and the matrix below note each director’s and director nominee’s relevant experience, qualifications, and skills relative to this list.

Skills/Competencies

We primarily serve the semiconductor, electronics and packaging, and specialty industrial markets. Directors with education and experience in technologies in these markets provide valuable perspectives on our research and development efforts, competing technologies, the products and processes we develop, our manufacturing and assembly, and the markets in which we compete.

Directors with a background in mergers and acquisitions and business development provide insights into developing and implementing strategies for growing our business. Useful experience in this area includes

skills in assessing and analyzing the “fit” of a proposed acquisition with our long-term strategy, valuing transactions, and assessing management’s integration plans and overseeing integration activities for completed acquisitions into our existing operations.

Directors who have served in senior leadership positions are important to us because they have the experience and perspective to analyze, shape, and oversee the execution of important operational and policy issues.

Directors with public company board experience understand the dynamics and operation of a corporate board, the relationship of a public company board to the Chief Executive Officer and other executive officers, the legal and regulatory landscape in which public companies must operate, and how to oversee an ever-changing mix of strategic, operational, and compliance-related matters.

We are a global organization with manufacturing, research and development, and sales offices in many countries. We sell our products to thousands of customers worldwide and a significant portion of our revenues are from sales to customers in international markets. Our manufacturing facility locations include Austria, Brazil, Canada, China, Czech Republic, France, Germany, India, Israel, Italy, Malaysia, Mexico, Romania, Singapore, South Korea, and the United States. Because of these factors, directors with international experience can provide valuable business, regulatory, and cultural perspectives regarding many important aspects of our business.

Functional Background

Directors with knowledge of financial markets, financing operations, and accounting and financial reporting processes assist the Board of Directors with advising on and overseeing our capital structure, our financing and investing activities as well as our financial reporting and internal controls.

Our products incorporate sophisticated technologies to measure, monitor, deliver, analyze, power, control, and improve complex semiconductor and advanced manufacturing processes, thereby enhancing uptime, yield, and throughput for our customers. Following our acquisition of Atotech Limited, or Atotech, in August 2022, which we refer to as the Atotech Acquisition, we also possess a broad portfolio of specialty chemistry solutions for surface finishing, functional coating, and corrosion resistance applications. We have developed, and continue to develop, new products to address industry trends. Directors with education and experience in engineering and research and development provide valuable perspectives regarding our research and development efforts, competing technologies, the products and processes we develop, our manufacturing and assembly, and the markets in which we compete.

Directors with a regulatory, legal, or governance background can assist the Board of Directors in fulfilling its oversight responsibilities regarding our compliance, engagement with regulatory authorities, and governance structure.

Directors with marketing, brand management and sales experience can provide expertise and guidance as we seek to expand the markets in which we compete, grow sales, and strengthen our brands.

As we operate in many cyclical markets, with rapid demand changes, and have a broad footprint of international manufacturing operations, understanding of and experience with manufacturing and other operational processes are valuable assets to our Board of Directors.

The markets we serve increasingly rely on digitization and electronic connectivity as growth drivers, including, for example, the Internet of Things, or IoT. Further, we rely on various information technology networks and systems, some of which are managed by third parties, to process, transmit, and store electronic information and to carry out and support a variety of business activities. The safety and security of our digital information, and the digital information of our customers, suppliers, and other business partners, are paramount to our success. Directors who have a sophisticated understanding of global digitization and/or cybersecurity literacy can assist with the Board of Directors’ oversight of driving future growth and securing our digital information in the rapidly evolving digital landscape.

Personal Demographics

Representation of a mix of ages, genders, and races brings diversity of thought to the Board of Directors and helps expand the Board of Directors’ understanding of the needs and perspectives of all of our stakeholders. In addition, we consider the tenure each director has on our Board of Directors to ensure the continued independence and effectiveness of the Board of Directors.

Board Skills Matrix

The below matrix and the directors’ biographies note each director’s relevant experience, qualifications, and skills relative to the skills and experience we consider important for our directors.

Directors

1

2

3

4

5

6

7

8

9

SKILL/COMPETENCIES

• Industry Experience

✓

✓

✓

✓

✓

✓

• M&A/Business Development Experience

✓

✓

✓

✓

✓

✓

✓

• CEO/COO/CFO Experience

✓

✓

✓

✓

✓

✓

✓

✓

• Experienced Public Company Director

✓

✓

✓

✓

✓

• International Experience

✓

✓

✓

✓

✓

✓

✓

FUNCTIONAL BACKGROUND

• Accounting/Finance

✓

• Engineering/R&D

✓

✓

✓

✓

• Regulatory/Legal/Governance

✓

✓

• Marketing/Sales

✓

✓

✓

✓

• Operations

✓

✓

✓

• Digitization/Cybersecurity/loT

✓

✓

PERSONAL DEMOGRAPHICS

• Tenure (years)

5

2

9

3

3

7

11

4

0

• Age

55

57

66

64

60

69

62

56

66

Board Diversity Matrix

The below matrix shows diversity statistics for our directors as of April 5, 2023.

Demographic Ratio Graphs

The following demographic ratio graphs show data for our directors.

PROPOSAL TWO – ADVISORY VOTE ON EXECUTIVE COMPENSATION

The Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, or the Dodd-Frank Act, enables our shareholders to vote to approve, on a non-binding, advisory basis, the compensation of our Named Executive Officers as disclosed in this proxy statement under the heading “Executive Compensation,” including “Compensation Discussion and Analysis,” the tabular disclosure regarding such compensation, and the accompanying narrative disclosure. This vote is not intended to address any specific item of compensation but rather the overall compensation of our Named Executive Officers and the philosophy, policies, and practices of executive compensation described in this proxy statement. The advisory vote is not a vote on our compensation practices for non-executive employees or our Board of Directors. The Dodd-Frank Act requires the Company to hold the advisory vote on executive compensation at least once every three years, but we have elected to submit the advisory vote to shareholders annually.

As described in detail under the heading “Executive Compensation — Compensation Discussion and Analysis,” our executive compensation program is designed to attract, motivate, and retain our executive officers, who are critical to our success. Under this program, our executive officers are rewarded for the achievement of specific short-term and long-term goals. Please see the “Compensation Discussion and Analysis” for additional details about our executive compensation program and philosophy, including information about the compensation of our Named Executive Officers.

The Compensation Committee continually reviews the compensation program for our executive officers to ensure it achieves the desired goals of aligning our executive compensation structure with our shareholders’ interests and current market practices. At the 2022 Annual Meeting of Shareholders, our shareholders overwhelmingly approved our executive compensation, with over 97% of the votes cast voting in favor of the “say-on-pay” proposal. The Compensation Committee considered the results of the 2022 “say-on-pay” vote, and based upon strong shareholder support, determined that our executive compensation program did not require any material changes in response to the 2022 “say-on-pay” vote.

Our Board of Directors is asking shareholders to approve a non-binding advisory vote on the following resolution:

RESOLVED, that the compensation paid to the Company’s Named Executive Officers, as disclosed pursuant to the compensation disclosure rules of the SEC, including the Compensation Discussion and Analysis, the compensation tables, and any related material disclosed in this proxy statement, is hereby approved.

This vote on the compensation of our Named Executive Officers is advisory, and therefore not binding on the Company, the Compensation Committee, or our Board of Directors. Our Board of Directors and our Compensation Committee value the opinions of our shareholders and, to the extent there is any significant vote against the Named Executive Officers’ compensation as disclosed in this proxy statement, we will consider our shareholders’ concerns and the Compensation Committee will evaluate whether any actions are necessary to address those concerns.

THE BOARD OF DIRECTORS BELIEVES THAT THE PROPOSAL TO APPROVE, ON A NON-BINDING ADVISORY BASIS, THE EXECUTIVE COMPENSATION CONTAINED IN THIS PROXY STATEMENT IS IN THE BEST INTERESTS OF MKS AND OUR SHAREHOLDERS AND THEREFORE RECOMMENDS A VOTE “FOR” THIS PROPOSAL.

PROPOSAL THREE – ADVISORY VOTE REGARDING FREQUENCY OF ADVISORY VOTES ON EXECUTIVE COMPENSATION

We are also asking shareholders to cast a non-binding, advisory vote on whether an advisory vote to approve the compensation of our Named Executive Officers as described in Proposal Two above (“say-on-pay vote”) should take place every year, every two years, or every three years.

Currently, a say-on-pay vote is submitted to our shareholders every year. The advisory vote on the frequency of the say-on-pay vote is a non-binding vote as to how often the say-on-pay vote should occur: every year, every two years, or every three years. Section 14A of the Securities Exchange Act of 1934, as amended, or the Exchange Act, requires us to submit a non-binding advisory vote on the frequency of the say-on-pay vote at least once every six years to determine whether advisory votes on executive compensation, such as Proposal Two, should be held every one, two or three years. On May 10, 2017, we held an annual meeting of shareholders at which shareholders voted on, among other matters, a non-binding proposal regarding the frequency of future say-on-pay votes. At that meeting, a majority of the votes cast on the frequency proposal were cast in favor of holding annual say-on-pay votes, and after considering the voting results, our Board of Directors decided to conduct an advisory vote on the compensation of our Named Executive Officers on an annual basis until the next advisory vote on the frequency of such say-on-pay votes.

After careful consideration, our Board of Directors has determined that a non-binding, advisory vote on executive compensation that occurs on an annual basis continues to be the most appropriate option for the Company, and therefore our Board of Directors recommends that shareholders approve continuing to hold the advisory vote on the compensation of our Named Executive Officers every year.

In formulating its recommendation, our Board of Directors considered that an annual say-on-pay vote will allow our shareholders to provide us with their direct input on our compensation philosophy, policies, and practices as disclosed in our proxy statement every year. While the Company currently recommends a vote in favor of an annual vote, you may cast your vote on your preferred voting frequency by choosing the option of one year, two years, three years or abstaining from voting when you vote on this proposal. However, because this vote is advisory and non-binding, the Board of Directors may decide that it is in the best interests of our shareholders and the Company to hold a say-on-pay vote more or less frequently than the option approved by our shareholders.

THE BOARD OF DIRECTORS BELIEVES THAT HAVING AN ADVISORY VOTE TO APPROVE EXECUTIVE COMPENSATION ONCE EVERY YEAR IS IN THE BEST INTERESTS OF MKS AND OUR SHAREHOLDERS AND THEREFORE RECOMMENDS A VOTE “FOR” AN ADVISORY VOTE ON EXECUTIVE COMPENSATION ONCE EVERY YEAR.

PROPOSAL FOUR – RATIFICATION OF SELECTION OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

Our Audit Committee has selected PricewaterhouseCoopers LLP, or PwC, as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2023. PwC was our independent registered public accounting firm for the fiscal year ended December 31, 2022.

Representatives of PwC have been invited to and are expected to attend the 2023 Annual Meeting. They will have the opportunity to make a statement if they so desire and will be available to respond to appropriate questions from shareholders. In the event that the ratification of the selection of PwC as our independent registered public accounting firm is not obtained at the 2023 Annual Meeting, the Board of Directors will reconsider its appointment.

THE BOARD OF DIRECTORS BELIEVES THAT THE PROPOSAL TO RATIFY THE SELECTION OF PWC AS OUR INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM FOR THE FISCAL YEAR ENDING DECEMBER 31, 2023 IS IN THE BEST INTERESTS OF MKS AND OUR SHAREHOLDERS AND THEREFORE RECOMMENDS A VOTE “FOR” THIS PROPOSAL.

CORPORATE GOVERNANCE

Board Independence

The Board of Directors has determined that all of the members of the Board of Directors, other than Mr. Colella and Dr. Lee, are independent as defined under applicable Nasdaq rules. Mr. Colella is not independent as he received a retirement payment from the Company in July 2020 in connection with his previous role as our Chief Executive Officer, and under applicable Nasdaq rules, there is a three-year look-back period from the determination of independence that is applicable to such payment. Dr. Lee is not independent as he currently serves as our President and Chief Executive Officer.

Board Leadership Structure

Since 2005, we have separated the roles of Chief Executive Officer and Chair of the Board of Directors in recognition of the differences between the two roles. The Chief Executive Officer is responsible for setting the strategic direction of the Company and the day-to-day leadership and performance of the Company, while the Chair of the Board of Directors provides guidance to the Chief Executive Officer, sets the agenda for Board meetings, and presides over meetings of the Board of Directors.

In addition, our Corporate Governance Guidelines provide that during any period in which the Chair of the Board of Directors is not an independent director, and in such other instances as the Board of Directors may determine from time to time, a Lead Director shall be elected by and from the independent directors. As Mr. Colella, the Chair of our Board of Directors, is not independent, we are currently obligated under our Corporate Governance Guidelines, which are posted on our website at www.mks.com/corporate-governance under Corporate Governance Documents, to have a Lead Director. Dr. Moloney has served as our Lead Director since 2020.

The primary role of the Lead Director is to serve as a liaison between the independent directors and the Chair of the Board of Directors and/or the Chief Executive Officer and to represent the independent directors, as appropriate. Pursuant to our Corporate Governance Guidelines, the Lead Director shall, among other matters:

Our Board of Directors believes that its leadership structure is appropriate at this time for our Company because it strikes an effective balance between management and independent leadership participation in the Board of Directors’ process.

Communications from Shareholders

The Board of Directors will give attention to written communications that are submitted by shareholders and will respond if appropriate. The Chair of the Nominating and Corporate Governance Committee, with the assistance of our General Counsel, is primarily responsible for monitoring communications from shareholders and for providing copies or summaries to the other directors as he or she considers appropriate. Communications are forwarded to all directors if they relate to important substantive matters and include suggestions or comments that the Chair of the Nominating and Corporate Governance Committee considers to be important for the directors to know. In general, communications relating to corporate governance and long-term corporate strategy are more likely to be forwarded than communications relating to ordinary business affairs, personal grievances, and matters as to which we tend to receive repetitive or duplicative communications.

Shareholders who wish to send communications on any topic to the Board of Directors should address such communications to the Board of Directors in care of Kathleen F. Burke, Esq., Executive Vice President, General Counsel and Secretary, MKS Instruments, Inc., 2 Tech Drive, Suite 201, Andover, MA 01810.

Code of Business Conduct and Ethics

We have adopted a Code of Business Conduct and Ethics that applies to all of our directors, officers, and employees (including the principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions), which is posted on our website at www.mks.com/corporate-governance under Corporate Governance Documents. We intend to disclose on our website any amendments to, or waivers for our executive officers or directors from, our Code of Business Conduct and Ethics.

Board’s Role in Risk Oversight

Management is responsible for the day-to-day management of risks the Company faces, while the Board of Directors, as a whole and through its committees, has the ultimate responsibility for the oversight of risk management. Senior management attends quarterly meetings of the Board of Directors, provides presentations on operations, including significant risks, and is available to address any questions or concerns raised by the Board of Directors. Additionally, our three standing board committees assist the Board of Directors in fulfilling its oversight responsibilities in certain areas of risk. Pursuant to its charter, the Audit Committee coordinates the Board of Directors’ oversight of the Company’s internal controls over financial reporting, disclosure controls and procedures, and code of business conduct and ethics. The Audit Committee also is responsible for discussing the Company’s policies with respect to financial risk assessment and financial risk management and overseeing the steps management has taken with respect to data privacy and cybersecurity risk exposure. Management regularly reports to the Audit Committee on these areas. The Compensation Committee assists the Board of Directors in fulfilling its oversight responsibilities with respect to the management of risks arising from our compensation policies and programs as well as succession planning. The Nominating and Corporate Governance Committee assists the Board of Directors in fulfilling its oversight responsibilities with respect to the management of risks associated with board organization, membership and structure, succession planning for our directors, corporate governance, and environmental, social and governance, or ESG, including climate-related risks.

In addition, from time to time, the Board of Directors may constitute a special committee to focus on a particular matter or risk. As previously disclosed, on February 3, 2023, we identified that we had become subject to a ransomware event and took immediate action to activate our incident response and business continuity protocols to contain the incident. Our Board of Directors responded quickly and constituted a special committee of the Board for cybersecurity, which included Mr. Colella, the Chair of our Board, Ms. Mora, the Chair of our Audit Committee, and Mr. Cannone and Mr. Donahue, each a member of our Audit Committee, to oversee the investigation, recovery, and restoration phases following the incident. The special committee held 15 meetings during the first two months following the identification of the incident. At these meetings, our Chief Executive Officer, our Chief Financial Officer, our General Counsel, our Executive Vice President of Operations and Corporate Marketing, and our Chief Information Officer reported to the special committee on various aspects of the incident, including the IT forensic investigation, business restoration and recovery activities, and the impact of the incident on our annual audit and assessment of internal controls as well as the filing of our Annual Report on Form 10-K for the year ended December 31, 2022. The Special Committee continues to oversee the response to the incident.

When any of the committees receives a report related to material risk oversight, the chair of the relevant committee reports on the discussion to the full Board of Directors.

Transactions with Related Persons

Our code of business conduct and ethics sets forth the general principle that our directors, officers, and employees should refrain from engaging in any activity having a personal interest that presents a conflict of interest. The code of business conduct and ethics prohibits directors, officers, and employees from engaging in any activity that may reasonably be expected to give rise to a conflict of interest or to adversely affect our interests. The code of business conduct and ethics provides that all employees are responsible for disclosing to the Company any transaction or relationship that reasonably could be expected to give rise to a conflict of interest, and executive officers and directors must report such transactions to the Board of Directors, which shall be responsible for determining whether such transaction or relationship constitutes a conflict of interest.

In addition, our written Related Person Transaction Procedures set forth the procedures for reviewing transactions that could be deemed to be “related person transactions” (defined as transactions required to be disclosed pursuant to Item 404 of Regulation S-K of applicable U.S. Securities and Exchange Commission, or SEC, regulations). In accordance with these procedures, directors and executive officers are required to submit annual certifications regarding interests and affiliations held by them and certain of their family members. We then review our records to determine whether we have engaged in any transactions since the beginning of our prior fiscal year with such affiliated persons and entities or with any person or entity known by MKS to be the beneficial owner of more than 5% of our voting securities, and provide a summary to the Audit Committee of any such material transaction in which the related person has a direct or indirect interest. In accordance with the procedures, the Audit Committee reviews any such transactions (including, but not limited to, transactions constituting related person transactions). In reviewing any such transaction, the Audit Committee considers, among other things, the related person’s interest in the transaction, the approximate dollar value of the transaction, whether the transaction was undertaken in the ordinary course of business, whether the terms of the transaction were at arm’s length, the purpose and potential benefits to the Company of the transaction, and whether the transaction is in the best interests of the Company. The Audit Committee may, in its sole discretion, impose such conditions as it deems appropriate in connection with any related person transaction. In accordance with the Audit Committee charter, the Audit Committee reviews the Related Person Transaction Procedures from time to time.

Mr. Wild, a director of the Company, was President and Chief Executive Officer and a director of Atotech prior to the closing of the Atotech Acquisition for a total purchase price of $5.7 billion. As a result of the termination of Mr. Wild’s employment immediately prior to the closing of the Atotech Acquisition, under the terms of his Atotech employment agreement and his Atotech award agreements for time-based restricted stock units and performance-based restricted stock units, Mr. Wild received approximately $4.5 million immediately following the Atotech Acquisition and will receive approximately $1.1 million on the 18-month anniversary of the Atotech Acquisition.

Carlyle Partners VI Cayman Holdings, L.P., CEP IV Participations, S.à r.l. SICAR, and Gamma Holding Company Limited, which we refer to collectively as Carlyle, collectively beneficially owned approximately 13% of the Company’s outstanding voting shares as of March 8, 2023, based on a filing they made with the SEC. Carlyle was the controlling shareholder of Atotech prior to the Atotech Acquisition. In connection with the Atotech Acquisition,

on the closing date of the Atotech Acquisition, the Company and Carlyle entered into an investment rights agreement, pursuant to which the Company granted Carlyle certain registration rights with respect to the shares of Common Stock Carlyle received as a result of the Atotech Acquisition, or the Company Shares.

Wellington Management Group LLP, Wellington Group Holdings LLP, Wellington Investment Advisors Holdings LLP, and Wellington Management Company LLP, which we refer to collectively as the Wellington Group, previously collectively beneficially owned more than 5% of the Company’s outstanding voting shares. Based on filings they made with the SEC, the Wellington Group collectively beneficially owned approximately 8% of the Company’s outstanding voting shares as of March 2, 2022 and approximately 3% of the Company’s voting shares as of March 8, 2023. Wellington Management LLP, an affiliate of the Wellington Group, managed a cash and investment account of MKS with an average cash balance of approximately $306 million in 2022 before MKS withdrew all funds from the account in October 2022. MKS paid Wellington Management LLP approximately $257,000 for these cash and investment management services in 2022. Wellington Management LLP was required to manage this account in accordance with, and subject to, the Company’s Corporate Investment Policy, which establishes clear guidelines for acceptable investments.

As part of our Related Person Transaction Procedures, our Audit Committee reviewed the foregoing relationships with Mr. Wild, Carlyle, and the Wellington Group.

Board of Director Meetings and Committees of the Board of Directors

The Board of Directors held nine meetings in 2022. During 2022, each director attended at least 75% of the aggregate of the total number of meetings of the Board of Directors and the total number of meetings of all committees of the Board of Directors on which he or she served. Pursuant to our Corporate Governance Guidelines, directors are encouraged to attend our annual meeting of shareholders. All of the directors then serving on the Board of Directors attended the 2022 Annual Meeting of Shareholders.

The Board of Directors has established three standing committees — Audit, Compensation, and Nominating and Corporate Governance — each of which operates under a charter that has been approved by the Board of Directors. Each committee’s current charter is posted on our website at www.mks.com/corporate-governance under Corporate Governance Documents.

Audit Committee

The Audit Committee consists of Ms. Mora (Chair), Mr. Cannone, Mr. Donahue, and Mr. Wild. Mr. Wild joined the Audit Committee in October 2022, shortly after he joined the Board of Directors. The Board of Directors has determined that each of Ms. Mora and Mr. Cannone is an “audit committee financial expert” as defined in applicable SEC regulations. Each member of the Audit Committee also meets the requirements for independence under applicable Nasdaq and SEC rules. The Audit Committee’s responsibilities include:

The Audit Committee held five meetings in 2022.

Compensation Committee

The Compensation Committee consists of Mr. Batra (Chair), Dr. Moloney, and Ms. Mora. Each member of the Compensation Committee meets the requirements for independence under applicable Nasdaq and SEC rules. The Compensation Committee’s responsibilities include:

The Compensation Committee held six meetings in 2022. See the section below entitled “Executive Compensation — Compensation Discussion and Analysis” for further information about the role of the Compensation Committee and the scope of its activities.

Compensation Risk Assessment

Our Compensation Committee engaged its independent compensation consultant, Pearl Meyer & Partners, LLC, or Pearl Meyer, to conduct a risk assessment of our compensation programs and practices to understand if any risks exist that are reasonably likely to have a material adverse effect on our Company, and the results were reviewed by our Compensation Committee. Based on this assessment, our Compensation Committee concluded that our compensation programs and practices, as a whole, are appropriately structured and do not pose a material risk to our Company. Our compensation programs are intended to reward our executive officers and other employees for strong performance over the long-term, with consideration to short-term actions and results that strengthen and grow our Company. We believe our compensation programs provide the appropriate balance between short-term and long-term incentives, focusing on sustainable and profitable growth for our Company.

Compensation Committee Interlocks and Insider Participation

In 2022, Mr. Batra, Dr. Moloney, and Ms. Mora served on the Compensation Committee. None of the members of the Compensation Committee during 2022 were, at any time, officers or employees of MKS or our subsidiaries, and none of them had any relationship with us requiring disclosure under applicable SEC rules and regulations. None of our executive officers serves, or has served, as a member of the Board of Directors or Compensation Committee (or other committee serving an equivalent function) of any other entity which has one or more executive officers serving as a member of our Board of Directors or Compensation Committee.

Nominating and Corporate Governance Committee

The Nominating and Corporate Governance Committee consists of Dr. Moloney (Chair), Mr. Batra, and Ms. Warner. Each member of the Nominating and Corporate Governance Committee meets the requirements for independence under applicable Nasdaq and SEC rules. The Nominating and Corporate Governance Committee’s responsibilities include:

The Nominating and Corporate Governance Committee held three meetings in 2022.

For information relating to the nomination of directors, see “Director Candidates” below.

Director Candidates

The Nominating and Corporate Governance Committee recommended to the Board of Directors that the director nominees be nominated by the Board of Directors for election as Class III Directors. The Nominating and Corporate Governance Committee utilizes a number of processes to identify and evaluate director candidates, including the engagement of a third-party executive search firm and other resources to identify potential director candidates, as needed. Activities relating to identifying and selecting nominees include Board assessments of each incumbent director nominee for the current year, requests to Board members and others for recommendations of potential candidates, meetings from time to time to evaluate biographical information and background material relating to potential candidates, and interviews of selected candidates by the members of the Nominating and Corporate Governance Committee and other members of the Board of Directors. The Nominating and Corporate Governance Committee recommended to the Board of Directors the nomination of Mr. Cannone and Mr. Donahue for election at the 2023 Annual Meeting.

In considering whether to recommend any particular candidate for inclusion in the Board of Directors’ slate of recommended director nominees, the Nominating and Corporate Governance Committee applies the criteria attached to the Company’s Corporate Governance Guidelines. These criteria include the candidate’s integrity, business acumen, knowledge of our business and industries, effectiveness, experience, diligence, conflicts of interest, and the ability to act in the interests of all shareholders. The Nominating and Corporate Governance Committee does not assign specific weights to particular criteria and no particular criterion is a prerequisite for each prospective nominee. The Nominating and Corporate Governance Committee also assesses the candidate’s professional background and skills against those of the existing Board members to ensure a breadth and diversity of expertise that suits the Company’s current and future business risks, industries, and challenges. See “Directors — Board Skills Matrix.” Nominees shall not be discriminated against on the basis of race, religion, national origin, sex, sexual orientation, disability, or any other basis proscribed by law. While the Nominating and Corporate Governance Committee does not have a formal policy with respect to diversity, the Board of Directors and the Nominating and Corporate Governance Committee believe that it is essential that the members of the Board of Directors represent diverse viewpoints, and the Nominating and Corporate Governance Committee actively seeks diverse candidates for the pool from which candidates are chosen. In considering candidates for the Board of Directors, the Nominating and Corporate Governance Committee considers the entirety of each candidate’s credentials in the context of these standards. We believe that the backgrounds and qualifications of our directors, considered as a group, should provide a composite mix of experience, knowledge, and abilities that will allow the Board of Directors to fulfill its responsibilities.

Shareholders may recommend individuals to the Nominating and Corporate Governance Committee for consideration as potential director candidates by submitting their names, together with appropriate biographical information and background material and a statement as to whether the shareholder or group of shareholders making the recommendation has beneficially owned at least $2,000 in market value or 1% of our Common Stock, whichever is less, for at least a year as of the date such recommendation is made, to the Nominating and Corporate Governance Committee, in care of Kathleen F. Burke, Esq., Executive Vice President, General Counsel and Secretary, MKS Instruments, Inc., 2 Tech Drive, Suite 201, Andover, MA 01810. Assuming that appropriate biographical and background material has been provided on a timely basis, the Nominating and Corporate Governance Committee will evaluate shareholder-recommended candidates by following substantially the same process, and applying the same criteria, as it does in considering other candidates.

Shareholders also have the right under our By-Laws to directly nominate director candidates, without any action or recommendation on the part of the Nominating and Corporate Governance Committee or the Board of Directors, by following the procedures set forth under the heading “Deadline for Submission of Shareholder Proposals for the 2024 Annual Meeting” below.

ENVIRONMENTAL, SOCIAL, AND GOVERNANCE

Governance

ESG is a key priority for MKS and our leaders. As such, our ESG Program and overall ESG Management System is overseen by the CEO and the Nominating and Corporate Governance Committee.

MKS’ cross-functional ESG Steering Committee meets throughout the year, and sets program strategy, defines annual objectives, provides guidance on high-level tactics to achieve its stated objectives, communicates the ESG Program to internal and external stakeholders, and monitors ESG industry trends. In accordance with its charter, the Nominating and Corporate Governance Committee also reviews and reports to the Board of Directors on the Company’s ESG strategy, goals, and initiatives, including climate-related risks and opportunities as well as the impact of other ESG issues on the Company.

In addition, our leadership approach is based on our commitment to conduct business with the highest standards of integrity. Our Code of Business Conduct and Ethics and our Human Rights and Labor Standards Policy are designed to ensure that we deliver on this commitment every day.

Human Capital Management

We are committed to our people and strive to foster a diverse, equitable, and inclusive community, invest in continuous learning and development, engage meaningfully with employees, offer a competitive compensation and benefits program, and provide a safe and healthy workplace. We believe that diversity of gender, race, ethnicity, sexual orientation, culture, education, background, and experience fuels innovation and results as well as enables our employees to succeed. Our executive team is comprised of 22% female members and 22% racially diverse members, our Board of Directors is comprised of 33% female members, 22% racially diverse members and 11% LGBTQ+ members, and our Lead Director is a woman.

In 2022, we continued to offer diversity, equity and inclusion, or DE&I, training for all employees and bias awareness training for our global talent acquisition and management teams. We proactively provide our hiring managers with diverse candidate slates in our employee recruiting process and, in accordance with our Corporate Governance Guidelines, seek diverse candidates for the pool from which our Board of Director nominees are chosen. We also regularly conduct robust analyses of pay practices across gender globally and other diversity factors within the United States to detect any existing disparities within base and total compensation, taking prompt and effective action to correct any identified disparities.

MKS is committed to investing in learning and professional development. Our employees have access to a wide range of programs, classes, and resources to help them excel in their careers and share what they learn with their colleagues. Our performance management process includes performance feedback and career development discussions that are dynamic and actionable throughout the year. In 2022, we continued to broadly roll out courses to develop our focus on employee engagement, change management, and leadership excellence. Over the past three years, approximately 320 of our leaders around the world also completed a six-week DE&I course hosted by a consulting firm recognized as best-in-class in the area of DE&I capability building. In addition, we provide financial support for college and graduate education for U.S. employees and access to online learning for all employees in local languages to help further the careers of our entire workforce.

In 2022, we engaged a firm that specializes in corporate culture to conduct a global survey on company culture, in order to understand the values, beliefs, and behaviors that shape our organization. The results of the survey are expected to inform how we manage our business and build relationships. In addition, in 2022, MKS conducted its second annual global employee engagement survey, which, due to the timing of the closing of the Atotech Acquisition, did not include Atotech employees. The results of the survey were thoroughly assessed and shared with our CEO and executive leadership team as well as our Board of Directors, and areas of focus for the coming year were identified and communicated to employees. In 2023, we plan to include all employees in our third annual global employee engagement survey, using the feedback we receive to examine current practices and drive new initiatives. MKS is also committed to providing total compensation packages that attract, motivate, and retain our employees, as well as recognizing and rewarding each employee’s sustained performance and results. In

addition, we are committed to ensuring that our total compensation packages are externally competitive while supporting our business plans and strategies. As employee turnover is an indicator of employee satisfaction, we monitor turnover globally. MKS has a very stable and committed workforce, as evidenced by low voluntary turnover. Our 12-month rolling average for voluntary turnover at the end of 2022 was below 6%. Our employee average tenure is more than nine years.

Health & Safety

MKS is committed to providing a safe and healthy workplace for all employees. We accomplish this through compliance with applicable laws and regulations regarding workplace safety, including recognition and control of workplace hazards, tracking injury and illness rates, and maintaining detailed emergency and business continuity plans. We also offer employees and eligible family members a full range of health and wellness programs, as well as many clinical and administrative services.

In 2022, we instituted a formal Global MKS Management System for Environmental, Health, and Safety to protect our employees, other stakeholders, and the environment. We are implementing this strong foundation for MKS’ corporate Environmental, Health, and Safety system in a stepwise process across the organization into 2026.

Environmental Management

We value the environment and the communities in which we live and work. We are committed to operating our business in an environmentally and socially responsible manner, in tandem with our employees, customers, suppliers, and communities.

Innovation is a key part of our ability to sustain our product differentiation and increase our relevance to customers. Our products are used in a broad range of industries and applications. In particular, our products contribute to indirectly driving positive environmental and social impact and progress, including through supporting the development of renewable energy infrastructure, enhancing health and safety for the customers who use our products, and increasing customers’ energy and water efficiencies in certain production processes.

As reported in our 2022 Environmental, Social, Governance Report, we were able to significantly increase the data coverage of our collection efforts for our greenhouse gas emissions, energy usage, and water usage across our sites in 2021. We assessed the Scope 3 emissions categories relevant to us and collected and calculated Scope 3 emissions metrics for not only business travel but also upstream transportation and distribution. We aim to continue evaluating and reporting on additional Scope 3 emissions categories that are applicable to our business. In addition, with a better understanding of our Scope 1 and 2 emissions baseline in 2021, we are engaging with our internal teams to develop a plan for how to reduce our operational emissions across the business. Following the Atotech Acquisition in August 2022, we are consolidating the environmental metrics for all of MKS and have begun working on developing emission reduction targets for the entire company.

Over the past few years, MKS’ business has evolved, and with the Atotech Acquisition, continues to grow in ways that we believe drive value for our stakeholders. While there have been many exciting developments at MKS, one goal remains the same: developing products that enable our customers to be more successful, our planet more sustainable, and our communities safer and more productive.

Additional information regarding MKS’ activities related to its people and sustainability can be found in our 2022 Environmental, Social, Governance Report, which is accessible through the ESG section of our website at www.mks.com/environmental-social-governance. Our Environmental, Social, Governance Report is updated periodically.

DIRECTOR COMPENSATION

Cash Compensation

The following table summarizes the cash compensation payable by us to non-employee directors in 2022:

In October 2022, following the Atotech Acquisition, the Board of Directors, upon the recommendation of the Compensation Committee, approved several changes to our non-employee director cash compensation program. The Compensation Committee recommended these changes after reviewing a competitive analysis of director compensation programs of our peer group prepared by the Committee’s independent compensation consultant, Pearl Meyer, and finding that certain components of board compensation fell below the median of our peer group. The table below sets forth the cash compensation payable by us to non-employee directors under the new cash compensation program effective as of January 1, 2023:

Retainers are pro-rated based on the time a director serves in the capacities listed. In addition, from time to time, the Board of Directors may establish special committees related to specific matters and may include a retainer for service on such special committees in its discretion.

Equity Compensation

Non-employee directors are eligible for awards under our 2022 Stock Incentive Plan, which is administered by the Compensation Committee. In 2022, under our director compensation program, non-employee directors received automatic grants of restricted stock units, or RSUs, on the date of the 2022 Annual Meeting of Shareholders, with a grant date value of $200,000, which RSUs shall vest in full on the day prior to the 2023 Annual Meeting.

If a new non-employee director joins our Board of Directors after our annual meeting of shareholders but before January 1st of the following year, he or she will be entitled to an initial RSU grant with a value equal to the annual RSU grant. In the event a non-employee director joins our Board of Directors during the period from January 1st through the date of that year’s annual meeting of shareholders, he or she will not be entitled to an initial RSU grant but will be entitled to the annual RSU grant on the date of the annual meeting of shareholders.

Director Compensation Table for 2022

The following table summarizes compensation earned by or paid to non-employee directors in 2022. Dr. Lee is excluded from the table because he was an executive officer in 2022 and his compensation is set forth in the Executive Compensation section below, under the heading “Executive Compensation Tables — Summary Compensation Table for 2022.”

AUDIT AND FINANCIAL ACCOUNTING OVERSIGHT

Audit Committee Report

The Audit Committee of our Board of Directors has reviewed our audited financial statements for the year ended December 31, 2022 and discussed them with our management.

The Audit Committee discussed with PricewaterhouseCoopers LLP, or PwC, our independent registered public accounting firm, the matters required to be discussed by the applicable requirements of the Public Company Accounting Oversight Board and the SEC.

The Audit Committee has received the written disclosures and the letter from our independent registered public accounting firm required by the applicable requirements of the Public Company Accounting Oversight Board regarding the independent accountant’s communications with the Audit Committee concerning independence, and has discussed with the independent accountant the independent accountant’s independence.

Based on the review and discussions referred to above, the Audit Committee recommended to our Board of Directors that the audited financial statements be included in our Annual Report on Form 10-K for the year ended December 31, 2022.

Respectfully submitted,

Elizabeth A. Mora, Chair

Peter J. Cannone III

Joseph B. Donahue

Geoffrey Wild

Principal Accountant Fees and Services

For the years ended December 31, 2022 and 2021, aggregate fees for professional services rendered by our independent registered public accounting firm, PwC, in the following categories were as follows:

Audit Fees

Audit fees billed for both years consisted of fees for professional services rendered for: (i) the audit of our annual consolidated financial statements, (ii) statutory audits, (iii) the review of our consolidated financial statements included in our quarterly reports on Form 10-Q, (iv) audit services related to other reports filed with the SEC, and (v) the audit of our internal controls over financial reporting as required by the rules and regulations promulgated under Section 404 of the Sarbanes-Oxley Act of 2002.

Audit-Related Fees

Audit-related fees for the year ended December 31, 2021 were for professional services associated with the then-pending Atotech Acquisition. There were no audit-related fees for the year ended December 31, 2022.

Tax Fees

Tax fees for the years ended December 31, 2022 and December 31, 2021 were for services related to tax compliance, including the preparation of tax returns, and tax planning and tax advice, including assistance with foreign operations and foreign tax audits.

All Other Fees

All other fees for the year ended December 31, 2022 were for accounting research software. All other fees for the year ended December 31, 2021 were for due diligence services performed in connection with potential acquisitions and for accounting research software.

In 2022 and 2021, all fees for professional services rendered by our independent registered public accounting firm were pre-approved pursuant to the Audit Committee’s pre-approval requirements, described below.

Pre-Approval Policy and Procedures

The Audit Committee’s charter sets forth the Audit Committee’s obligations relating to the approval of all audit and non-audit services that are to be performed by our independent registered public accounting firm. The

charter provides that we will not engage our independent registered public accounting firm to provide audit or non-audit services unless the service is pre-approved by the Audit Committee. In addition, we will not engage any other accounting firm to provide audit services unless such services are pre-approved by the Audit Committee. It is the Audit Committee’s policy that with respect to services performed or to be performed by PwC in connection with each fiscal year of the Company, the annual fees for non-audit services in such year shall not exceed one half of the aggregate fees payable to PwC for such year, without the prior express approval of the Audit Committee.

In connection with the foregoing, the Audit Committee may approve specific services in advance. In addition, from time to time, the Audit Committee may pre-approve specified types of services that are expected to be provided to us by our independent registered public accounting firm during the next 12 months. Any such pre-approval of types of services is detailed as to the particular service or type of service to be provided and is also generally subject to a maximum dollar amount.

The Audit Committee has also delegated to the Chair of the Audit Committee the authority to approve any audit or non-audit services to be provided to us by our independent registered public accounting firm. Any approval of services by the Chair of the Audit Committee pursuant to this delegated authority is reported on at the next meeting of the Audit Committee.

The Audit Committee has considered and determined that the provision of the non-audit services noted in the foregoing table is compatible with maintaining PwC’s independence.

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

The following table sets forth certain information with respect to the beneficial ownership of our Common Stock by (i) each shareholder known to us to be the beneficial owner of more than 5% of the outstanding shares of our Common Stock; (ii) the Named Executive Officers named in the Summary Compensation Table below; (iii) each of our current directors; and (iv) all of our directors and executive officers as a group. Unless otherwise indicated in the footnotes to the table, all equity amounts set forth in the table are as of March 8, 2023. The address for each of our directors and executive officers is: c/o MKS Instruments, Inc., 2 Tech Drive, Suite 201, Andover, Massachusetts 01810.

To our knowledge, there are no voting trusts or similar arrangements among any of the foregoing persons or entities with respect to the voting of shares of Common Stock.

EXECUTIVE OFFICERS

The following is a brief summary of the background of each of our current executive officers, other than Dr. Lee, whose background is described under the heading “Directors” above:

Our executive officers are appointed by the Board of Directors on an annual basis and serve until their successors are duly appointed and qualified. There are no family relationships among any of our executive officers or directors.

EXECUTIVE COMPENSATION

Compensation Discussion and Analysis

Introduction

The purpose of this section of our proxy statement is to provide an overview of our executive compensation program, our compensation philosophy and objectives, and the material decisions we made with respect to each element of our executive compensation program. Throughout this proxy statement, we refer to the “Named Executive Officers” listed below.

Effective upon the closing of the Atotech Acquisition, Mr. Henry, who previously served as our Senior Vice President, Corporate Marketing, Project Management Office and Global Service, assumed the position of Senior Vice President, Operations and Corporate Marketing, and Mr. Schreiner, who previously served as our Senior Vice President and Chief Operating Officer, assumed the position of Senior Vice President and Chief Operating Officer, Materials Solutions Division, which division refers to our newly acquired Atotech business. In addition, in February 2023, Mr. Bagshaw, Ms. Burke, Mr. Henry, and Mr. Schreiner, who each previously served as a Senior Vice President, assumed the position of Executive Vice President, to identify these officers as members of our executive management team.

Following this Compensation Discussion and Analysis, you will find a series of tables containing specific information about the compensation earned by or paid to our Named Executive Officers in 2022.

Executive Summary

Our Business

We enable technologies that transform our world. We deliver foundational technology solutions to leading edge semiconductor manufacturing, electronics and packaging, and specialty industrial applications. We apply our broad science and engineering capabilities to create instruments, subsystems, systems, process control solutions, and specialty chemicals technology that improve process performance, optimize productivity, and enable unique innovations for many of the world’s leading technology and industrial companies. Our solutions are critical to addressing the challenges of miniaturization and complexity in advanced device manufacturing by enabling increased power, speed, feature enhancement, and optimized connectivity. Our solutions are also critical to addressing ever-increasing performance requirements across a wide array of specialty industrial applications.

Company Performance in 2022

We executed well in 2022, despite a rapidly changing macroeconomic environment, continued supply chain constraints, and notable inflationary impacts.

2022 also marked a major advancement in our long-term strategy, as we completed the Atotech Acquisition. Atotech adds leading critical chemistry solutions for advanced printed circuit board (“PCB”) and package substrate manufacturing. Combined with our laser processing solutions, we now have a unique and comprehensive portfolio that positions us to accelerate customer technology roadmaps. Together with our leading portfolio of solutions enabling semiconductor manufacturing, MKS has established itself as a foundational technology enabler of the core building blocks of advanced electronic devices. Atotech also provides us with an attractive proprietary chemistry and equipment portfolio for general metal finishing, which aligns well with our strategy of leveraging core domain expertise to address a wide variety of specialty industrial applications.

Despite continued supply chain constraints, we delivered record revenue from the Semiconductor Market. Our global operations team executed well in navigating supply chain constraints amid record customer demand. At the same time, we remained focused on investing in innovation to drive technology enablement for our customers. MKS is well-positioned to remain a key beneficiary of long-term secular growth in demand for semiconductor capital equipment, given our broad and unique capabilities, which we believe enable more manufacturing steps than any other company in the industry.

In 2022, in an effort to provide further insight into our business, we updated our end market classifications by replacing Advanced Markets with two separate end markets, Electronics and Packaging, and Specialty Industrial, which more effectively reflect our distinct end-market opportunities. Our Electronics and Packaging Market refers to our opportunities in advanced PCB, package substrate, and display manufacturing. Our Specialty Industrial Market includes a broad array of applications across industrial, life and health sciences, and research and defense. Revenue from the Electronics and Packaging and Specialty Industrial Markets reached new records in 2022, primarily due to the Atotech Acquisition.

In 2022, key results include:

2022 Compensation Outcomes

Our executive compensation program is designed to reward our Named Executive Officers for performance and to align their interests with those of our shareholders. As a result of our financial performance in 2022, our Named Executive Officers received 100% of their target variable cash compensation under our Management Incentive Plan, which was measured against non-GAAP operating income after bonus and annualized cost savings, and 139% of their target performance-based equity compensation, which was measured against Adjusted EBITDA (each financial metric as further described under “Elements of Compensation” below). We believe these financial metrics are important to our shareholders because each is an indicator of how well we manage the operations and profitability of our Company. The successful alignment of our financial performance goals with our incentive payout opportunities for 2022 is evidenced by the fact that our Management Incentive Plan paid out at target achievement and our performance-based equity awards paid out at above-target achievement in a year where our Company achieved record revenue and strong non-GAAP operating income, annualized cost savings and Adjusted EBITDA.

Consideration of 2022 Advisory Vote on Executive Compensation

At our 2022 Annual Meeting of Shareholders, held on May 10, 2022, we submitted to our shareholders an advisory vote on executive compensation. Although annual advisory say-on-pay votes are non-binding, our Compensation Committee considers the outcome of this vote each year when making compensation decisions for our Named Executive Officers. At the 2022 Annual Meeting, our shareholders overwhelmingly approved our executive compensation, with over 97% of the votes cast voting in favor of the say-on-pay proposal.

The Compensation Committee considered the results of the 2022 say-on-pay vote, and based upon strong shareholder support, determined that our executive compensation program did not require any material changes in response to the 2022 say-on-pay vote. The Compensation Committee will continue to consider the views of our shareholders in connection with our executive compensation program, in addition to considering evolving best practices, market compensation information, and changing regulatory requirements. The Compensation Committee believes that the results of the 2022 say-on-pay vote were an endorsement of our compensation and pay decisions made in relation to our performance.

Compensation Philosophy and Objectives

The primary objectives of our executive compensation program are to:

We target each of our Named Executed Officers’ various compensation elements, including base salary, annual cash incentive compensation, and long-term equity incentive compensation, to be within a competitive range around median levels (plus or minus 15% of median) for each such respective position in the market. The competitive range is considered alongside other key factors when setting compensation levels, and final values may range from approximately the 25^th percentile to approximately the 75^th percentile, determined on an individual basis. In considering the compensation of our Named Executive Officers relative to the market, we also qualitatively assess each Named Executive Officer’s overall performance, tenure, and potential contributions to MKS’ ongoing growth. For 2022, the total target compensation of each of our Named Executive Officers fell within the competitive range of the median of our peer group.

Base salaries are designed to provide executives with a level of predictability and stability with respect to a portion of their total compensation package. Base salaries are a relatively small component of the overall pay packages of our Named Executive Officers because we believe a significant majority of executive compensation should be variable and based on performance.

Our annual cash incentive compensation program is designed to reward the attainment of short-term earnings and cost savings goals that drive the long-term growth of MKS. We believe that these goals are aligned with significant value creation, and that our plan creates a strong link between pay and performance while providing a meaningful incentive for our Named Executive Officers to deliver financial results that exceed our goals.

We provide our Named Executive Officers with long-term equity incentive compensation in the form of RSUs, approximately half of which are performance-based, in order to:

In order to further underscore our compensation values and enhance the efficacy of our pay programs, we also adhere to the following practices:

What We Do

What We Do Not Do

The following charts show the components of total target compensation on a percentage basis for our Chief Executive Officer and our other Named Executive Officers as a group for 2022.

When the Compensation Committee met in May 2021 to review the peer companies to be used to determine 2022 executive compensation, the Committee elected to remove KLA Corporation from and add Advanced Energy Industries, Inc., Ciena Corporation, and IDEX Corporation to the existing peer group, which at that time consisted of 17 U.S. publicly traded companies that had been primarily selected based on similar industry and size. In determining whether these companies remained appropriate for continued inclusion in the peer group, the Compensation Committee considered whether they had a revenue range relative to our trailing 12-month revenue as of December 31, 2020 between approximately 0.5 to 2.5 times and a market capitalization range relative to our market capitalization as of March 31, 2021 between approximately 0.3 and 3.0 times. The Compensation

Committee also considered secondary factors including other relevant peer groups, commonality of peers, other performance considerations, and whether a company is a competitor for talent. Publicly available compensation data from the following 19 peer companies was used in determining executive compensation for 2022:

In certain instances where robust peer group benchmark data was not available, our Compensation Committee utilized size and industry-appropriate broad survey data from Radford Data & Analytics, a third-party provider of compensation data and analytics.

Elements of Compensation

The following summarizes the compensation elements for our Named Executive Officers:

Base Salary

In October 2021, in anticipation of the new roles Mr. Henry and Mr. Schreiner would assume upon the closing of the Atotech Acquisition, our Compensation Committee approved salary increases of approximately 6% for each of Mr. Henry and Mr. Schreiner, effective upon the closing. These increases were to be inclusive of any 2022 annual merit increases. When our Compensation Committee set 2022 annual executive compensation in March 2022, the Atotech Acquisition was still pending and the closing date was uncertain. For this reason, the Compensation Committee approved 2022 annual salary increases that reflected the Company’s size pre-acquisition. Mr. Henry and Mr. Schreiner each received a salary increase of approximately 5%, Ms. Burke received approximately 4%, and Dr. Lee and Mr. Bagshaw each received approximately 3%. The increases for Mr. Henry and Mr. Schreiner reflected the existing roles they served in the Company. Upon the closing of the Atotech Acquisition in August 2022, when Mr. Henry assumed the position of Senior Vice President, Operations and Corporate Marketing and Mr. Schreiner assumed the position of Senior Vice President and Chief Operating Officer, Materials Solutions Division, Mr. Henry and Mr. Schreiner each received an additional salary increase of approximately 1%, which reflected the difference between their 5% 2022 annual salary increase and the 6% salary increase the Compensation Committee had approved in October 2021 in connection with their new roles following the Atotech Acquisition.

Listed below is the base salary for Dr. Lee, our President and Chief Executive Officer, in 2021 and 2022.

Listed below are the base salaries for our other Named Executive Officers in 2021 and 2022.

Our Compensation Committee did not make any material changes to Named Executive Officer salaries for 2023.

Annual Cash Incentive Compensation

For 2022, the Compensation Committee did not make any material changes to our annual cash incentive program. One administrative change was made to the program to consolidate our annual cash incentive plan and our profit improvement cash bonus plan into a single plan, the Management Incentive Plan.

Under the Management Incentive Plan, each Named Executive Officer was eligible to receive a performance bonus based on a specified percentage of base salary earned during the 2022 calendar year. Cash bonus payouts for 2022 under the Management Incentive Plan were based on two financial performance metrics, (i) non-GAAP operating income after bonus, which excluded any charges or income not related to the operating performance of the Company, and (ii) annualized cost savings, defined as profit enhancements or cost reductions approved by the Chief Executive Officer that result, on an annualized basis, in quantified and measured benefits to the Company’s financial performance. Any payout under the Management Incentive Plan is capped such that the payout would not exceed an amount equal to 200% of the Named Executive Officer’s Target Bonus Amount (defined below).

In 2022, payouts under the Management Incentive Plan were determined by multiplying each Named Executive Officer’s “Target Bonus Amount” by the Company’s percentage achievement of non-GAAP operating income and annualized cost savings, with certain caps as discussed below. Target Bonus Amount consists of each Named Executive Officer’s base salary earned in 2022, multiplied by his or her “Target Bonus Percentage,” as determined by our Compensation Committee. If a Named Executive Officer’s base salary and/or Target Bonus Percentage changed during 2022, the Named Executive Officer’s Target Bonus Amount was pro-rated based on the number of days in 2022 that the Named Executive Officer received such base salary and/or target award percentage. In October 2021, in anticipation of the new role Mr. Henry would assume upon the closing of the Atotech Acquisition, our Compensation Committee approved an increase in his Target Bonus Percentage of 5%, effective upon the closing. This increase was to be inclusive of any 2022 annual merit increase. When our Compensation Committee set 2022 annual executive compensation in March 2022, its decisions reflected the Company’s size pre-acquisition, given the uncertainty of the closing date of the Atotech Acquisition. It elected to increase the Target Bonus Percentage for each of Dr. Lee and Mr. Henry by 5% to better align their bonus opportunities with the market in their current roles and maintain the existing Target Bonus Percentage for each of Mr. Bagshaw, Ms. Burke, and Mr. Schreiner. Upon the closing of the Atotech Acquisition in August 2022, no adjustment was needed to Mr. Henry’s Target Bonus Percentage, as the increase approved by the Compensation Committee before and after the Atotech Acquisition was the same.

Listed below is the 2022 Target Bonus Percentage for each Named Executive Officer in 2021 and 2022.

In 2022, our Compensation Committee approved goals and associated incentive payout opportunities related to our 2022 non-GAAP operating income and annualized cost savings performance. Due to the cyclical nature and volatility of the markets in which we operate, including the consumer electronics market and semiconductor market, our Compensation Committee views it of paramount importance to set financial performance goals that are rigorous but attainable given the outlook for these markets for the coming year. For 2022, our Compensation Committee set target achievement for non-GAAP operating income at an amount that was greater than either target or actual achievement in 2021. Our Compensation Committee also set target achievement for annualized cost savings at an amount that was 60% greater than the target established in 2021.

The successful alignment of our financial performance goals with our incentive payout opportunities for 2022 is evidenced by the fact that our Management Incentive Plan paid out at 100% achievement in a year where we achieved record revenue and strong non-GAAP operating income and annualized cost savings.

Non-GAAP Operating Income Metric: In 2022, Named Executive Officers would receive the following percentage of their Target Bonus Amount under the non-GAAP operating income metric of the Management Incentive Plan, with proportional payments for achievement in between the Threshold Bonus Amount and the Maximum Bonus Amount.

If non-GAAP operating income before the calculation of bonus was greater than the Threshold Bonus Amount, but the inclusion of the bonus would result in an amount lower than the Threshold Bonus Amount, then only the portion of pre-bonus operating income above the Threshold Bonus Amount would be payable to Named Executive Officers on a pro rata basis. In 2022, for purposes of the Management Incentive Plan, non-GAAP operating income was $758.84 million. As a result, Named Executive Officers were eligible to receive 90% of their Target Bonus Amounts under this formula. The 2022 non-GAAP operating income calculation excludes restructuring charges, acquisition and integration costs and amortization of intangible assets, as well as the results of Atotech, which we acquired in August 2022.

Annualized Cost Savings Metric: Our Management Incentive Plan is also designed to incentivize profitability improvements during cyclical downturns in our business. In 2022, Named Executive Officers would receive the following percentage of their Target Bonus Amount under the annualized cost savings metric, with proportional payments for achievement in between these levels, subject to the limitations described below.

A Named Executive Officer would only be eligible to receive a payout under the annualized cost savings metric if the Named Executive Officer receives less than 100% of his or her Target Bonus Amount under the non-GAAP operating income metric and, in that case, the combined payout under both metrics could not exceed 100% of his or her Target Bonus Amount.

In 2022, for purposes of the Management Incentive Plan, annualized cost savings were $42.4 million. As a result, Named Executive Officers were eligible to receive 25% of their Target Bonus Amounts under this formula. However, because Named Executive Officers were eligible to receive 90% of their Target Bonus Amount under the non-GAAP operating income metric, and because the sum of the Target Bonus Amount under both metrics could not exceed 100%, the Target Bonus Amount under the annualized cost savings metric was reduced from 25% to 10%.

Listed below are our Named Executive Officers’ earned cash bonus payouts for 2022.

Our Compensation Committee did not make any material design changes to our annual cash incentive program for 2023.

Long-Term Equity Incentive Compensation

In October 2021, in anticipation of the new roles Mr. Henry and Mr. Schreiner would assume upon the closing of the Atotech Acquisition, our Compensation Committee approved the following time-based and performance-based RSUs to Mr. Henry and Mr. Schreiner, to be issued at the time the 2022 annual RSUs were awarded to the Named Executive Officers, assuming the closing had occurred. These RSU awards were to be inclusive of any 2022 annual merit awards.

When our Compensation Committee set 2022 annual executive compensation in March 2022, its decisions reflected the size of the Company pre-Atotech Acquisition, given the uncertainty of the closing date. It awarded the following time-based and performance-based RSUs to our Named Executive Officers. These awards reflected the existing roles Mr. Henry and Mr. Schreiner served in the Company. These RSUs vest in three equal annual installments. The performance-based RSUs are subject to a one-year performance metric described below.

Upon the closing of the Atotech Acquisition in August 2022, when Mr. Henry and Mr. Schreiner assumed their new roles, Mr. Henry and Mr. Schreiner each received an additional 226.66 performance-based RSUs with a grant date value of $25,000 (assuming 100% achievement) and 226.66 time-based RSUs with a grant-date value of $25,000, which reflected the difference between their 2022 annual RSU awards and the RSU awards the Compensation Committee had approved in October 2021 in connection with their new roles following the Atotech Acquisition.

With respect to performance-based RSUs, our goal is to select a Company financial metric that best aligns with our Company objectives. Since 2020, we have used Adjusted EBITDA (defined as the Company’s GAAP operating income excluding any charges or income not related to the operating performance of the Company plus depreciation and stock compensation expense), which we believe is an appropriate indicator of how effectively we manage the operations of our Company, while continuing to recognize the cyclical nature and volatility of the markets we serve, as well as to drive continued improvement in our Company’s operating model independent of revenue levels.

Further, we choose to measure Adjusted EBITDA over a one-year performance period because of the cyclical nature and volatility of our markets, making it challenging, and potentially counterproductive, to set multi-year performance targets. To ensure our executive officers are focused on our Company’s long-term performance, the performance-based RSUs vest over a three-year period in equal annual installments.

We use RSUs as our form of equity incentive compensation because we believe RSUs help to ensure that our executive officers’ interests are aligned with our shareholders’ interests in both a rising and a declining stock market. We believe RSUs are preferable to options, which have a relatively high accounting cost as compared to their potential value to the executive officer, and restricted stock, which gives the executive officer voting and dividend rights prior to full vesting. Also, because RSUs are worth more than options on the date of grant, we are able to grant fewer RSUs as compared to options, resulting in less dilution to shareholders’ holdings.

In 2022, our Named Executive Officers would have forfeited all of their performance-based RSUs if our Adjusted EDITDA was less than $630.36 million at a revenue level of $2.90 billion, or if such Adjusted EBITDA was less than $867.90 million at a revenue level of $3.50 billion (with intermediate Adjusted EBITDA minimum thresholds at different revenue levels in between). However, if we did achieve these Adjusted EBITDA threshold levels at the respective revenue levels identified, then our Named Executive Officers would receive 50% of their target performance-based RSUs. If our Adjusted EBITDA was $741.60 million at a revenue level of $2.90 billion or was $1.02 billion at a revenue level of $3.50 billion (with proportional thresholds in between), then our Named Executive Officers would receive 100% of their target performance-based RSUs. If our Adjusted EBITDA was at or above $815.76 million at a revenue level of $2.90 billion or was at or above $1.12 billion at a revenue level of $3.50 billion (with proportional thresholds in between), then our Named Executive Officers would receive the maximum of 200% of their target performance-based RSUs. If revenue was outside the range of $2.90 billion and $3.50 billion, then the performance target and payout would be calculated using the same payout formula. Proportional achievement levels would be made for Adjusted EBITDA between the minimum and maximum levels.

In 2022, because our revenue was $3.03 billion and our Adjusted EBITDA was $854.2 million, after excluding the results of Atotech, which we acquired in August 2022, as well as restructuring charges, acquisition and integration costs, amortization of intangible assets, depreciation of fixed assets and stock-based compensation expense, our Named Executive Officers received 139% of their target performance-based RSUs. In general, these performance-based RSUs, along with the time-based RSUs granted to our Named Executive Officers, vest in equal annual installments over three years from the original date of grant.

It is our practice to make an initial equity-based grant to all of our Named Executive Officers at the time they commence employment in an amount that is consistent with amounts granted to other executive officers in the industry at similar levels of seniority. We also may make equity-based grants to a Named Executed Officer in connection with a promotion or other change in position. In addition, we typically make an annual grant of equity-based compensation to our Named Executive Officers during the first fiscal quarter of each year. Discretionary equity-based awards may also be made throughout the year to provide an incentive to achieve a specific goal or to reward a significant achievement or for other reasons that the Compensation Committee determines. Our Compensation Committee did not make any discretionary equity-based awards to our Named Executive Officers in 2022.

Our Compensation Committee did not make any design changes to our 2023 annual equity incentive program.

Perquisites

Our Compensation Committee elected to discontinue perquisites effective December 31, 2020, with the exception that Mr. Bagshaw and Mr. Schreiner were permitted to retain their company-leased cars until the

expiration of their leases in May 2023 and November 2023, respectively, to avoid lease cancellation costs. Our Compensation Committee believes the discontinuation of perquisites allows us to simplify and more consistently align our compensation and benefits offerings with other employees, while placing greater focus on performance-based compensation.

Severance and Change-in-Control Provisions

Each of our Named Executive Officers is entitled to certain payments and benefits in the event his or her employment terminates under specified circumstances as described in the applicable agreement and subject to his or her entry into a release of claims. In addition, in exchange for these payments and benefits, each of these officers has agreed to be restricted from competing with the Company during and following his or her termination of employment for a twelve-month period. In addition, RSU agreements with our Named Executive Officers generally provide for acceleration of vesting in the event the executive’s employment is terminated without cause or the executive resigns for good reason within 24 months after a change-in-control event. The severance and change-in-control provisions are designed to be competitive in the marketplace, to provide security for each of our Named Executive Officers in the event that we are acquired and his or her respective position is impacted and to provide an incentive for our Named Executive Officers to stay with us through such a change-in-control event. These provisions are also intended to protect us from competitive harm by compensating our Named Executive Officers for agreeing to substantial non-compete provisions after employment termination. See “Executive Compensation Tables — Potential Payments Upon Termination or Change-in-Control” for more information about these agreements.

Compensation of our Chief Executive Officer

We entered into an employment agreement with Dr. Lee in November 2019 in connection with his promotion to Chief Executive Officer, effective as of January 1, 2020. The terms of Dr. Lee’s employment agreement reflected his role as the leader of our Company and the experience he brought to the position. For a detailed discussion of the material compensation terms of Dr. Lee’s employment agreement, including all amendments to this employment agreement, see “Executive Compensation Tables — Potential Payments Upon Termination or Change-in-Control.”

Compensation of our Other Named Executive Officers

We have entered into employment agreements with each of our other Named Executive Officers. For a detailed discussion of the material compensation terms of these executive employment agreements, including all amendments to these employment agreements, see “Executive Compensation Tables — Potential Payments Upon Termination or Change-in-Control.”

Compensation Consultant

We engage a compensation consultant to serve as an independent advisor to the Compensation Committee regarding compensation for our directors and our executive officers. The Compensation Committee utilizes the compensation consultant in the following ways:

Since May 2019, the Compensation Committee has engaged Pearl Meyer as its compensation consultant. The Compensation Committee has determined that the engagement of Pearl Meyer as a compensation consultant does not raise any conflicts of interest with MKS.

Role of our Chief Executive Officer

Our Chief Executive Officer reviews with the Compensation Committee the performance of all other Named Executive Officers and makes recommendations relating to compensation of such executive officers. Management develops proposed company financial goals for review and approval by the Compensation Committee for the annual cash incentive plan and long-term performance-based equity incentive compensation, develops proposals relating to potential changes in compensation programs for review and approval by the Compensation Committee, and provides the Compensation Committee and its advisors with information necessary to evaluate and implement compensation proposals and programs. Our Chief Executive Officer does not participate in discussions regarding his own compensation.

Governance Policies

Stock Ownership Guidelines

Our Stock Ownership Guidelines in effect as of December 31, 2022, which applied to members of the Board of Directors, the Chief Executive Officer and any other person who is or was a named executive officer while the guidelines were effective, provided that:

These guidelines were based, in each case, on values in effect as of December 31 of the applicable year. The Stock Ownership Guidelines provided for a phase-in period over five years to achieve the respective ownership goals. All Named Executive Officers and directors were in compliance with the Stock Ownership Guidelines as of December 31, 2022.

In February 2023, following our annual review of our Stock Ownership Guidelines, including a benchmarking analysis against peer companies, our Board of Directors enhanced our Stock Ownership Guidelines, effective as of February 2023, as follows:

Clawback Policy

Our Clawback Policy, which is applicable to incentive-based compensation (specifically our annual cash incentive plan and our performance-based RSUs) that is awarded to our current and former executive officers, provides that in the event we are required to prepare an accounting restatement due to fraud, misconduct, or material noncompliance with financial reporting requirements, we will use reasonable efforts to recover any amount in excess of what would have been paid to such executive officers (or such former executive officers) under the accounting restatement for any such incentive-based compensation during the three-year period preceding the restatement. The Compensation Committee may direct the Company to recover additional amounts of incentive-based compensation up to the entire amount, including different amounts from different executive officers, if the Compensation Committee concludes that executive officer fraud or misconduct directly caused or materially contributed to the accounting restatement.

Prohibition on Hedging and Pledging

Our Insider Trading Policy prohibits any of our directors or employees from engaging in purchases of financial instruments or other transactions that hedge or offset, or are designed to hedge or offset, any decrease in the market value of our securities (including pre-paid variable forward contracts, equity swaps, collars, and exchange funds), and prohibits such individuals from purchasing our securities on margin or pledging such securities as collateral for a loan.

Impact of Accounting on Executive Compensation

We account for stock-based compensation in accordance with the requirements of ASC 718. The Compensation Committee considers the impact of ASC 718 on our use of equity incentives as a key retention tool. The Compensation Committee regularly reviews its choice of equity incentives, taking into account both tax and accounting considerations.

COMPENSATION COMMITTEE REPORT

The Compensation Committee has reviewed and discussed the “Compensation Discussion and Analysis” required by Item 402(b) of Regulation S-K with management. Based on such review and discussions, the Committee recommended to the Board of Directors that the “Compensation Discussion and Analysis” be included in this proxy statement.

Respectfully submitted,

Rajeev Batra, Chair

Jacqueline F. Moloney

Elizabeth A. Mora

EXECUTIVE COMPENSATION TABLES

Summary Compensation Table for 2022

The following table sets forth the aggregate amounts of compensation earned by our Named Executive Officers in the years ended December 31, 2022, 2021, and 2020.